1. Technical Field
The present invention relates to a switching control apparatus and method of a two-phase switched reluctance motor.
2. Description of the Related Art
In a switched reluctance motor (hereinafter, referred to as a SRM), which is a motor having a form in which it has a switching control apparatus coupled thereto, both of a stator and a rotor are formed in a salient type structure.
Particularly, since only a stator part has a winding wound therearound and a rotor part does not include any type winding or permanent magnet, the SRM has a simple structure.
Due to this structural feature, the SRM has a significant advantage in view of manufacturing and production, and has good start-up characteristics and a large torque, similar to a direct current motor. In addition, the SRM requires less maintenance and has excellent characteristics in view of a torque per unit volume, efficiency, rating of a converter, and the like, such that the usage of the SRM has gradually increased in various fields.
The SRM as described above may have various types such as a single-phase, a two-phase, a three-phase, and the like. Among others, the two-phase SRM has a driving circuit simpler than that of the three-phase SRM, such that it has been significantly prominent in applications such as a fan, a blower, a compressor, and the like.
Further, in a switching control apparatus of the two-phase SRM, various schemes have been suggested and used in order to control current of a stator winding in a single direction. As one of the suggested schemes, there is a switching control apparatus using an asymmetric bridge converter for driving an existing alternate current motor.
The asymmetric bridge converter has two switches and diodes per each phase and has three operation modes.
Here, an operation mode 1 is a mode in which both of the two switches are turned on to apply DC power voltage to a winding, thereby increasing current, an operation mode 2 is a mode in which the two switches are simultaneously turned off to rapidly decrease the current, and an operation mode 3 is a mode in which when the current flows in the winding, one switch is turned off to circulate the current through one diode and switch and the winding, thereby slowly decreasing the current.
The asymmetric bridge converter operated as described above is excellent in view of diversity of a control among converters for driving an SRM and may independently control currents of each phase, such that the currents of two phases may be overlapped with each other. In addition, the asymmetric bridge converter is appropriate for high voltage and large capacity and has a relatively low switch rated voltage.
However, the switching control apparatus of the two-phase SRM as described above requires two lead wires per each phase, such that a wiring becomes complicated to increase a difficulty in designing the circuit.
In addition, since the switching control apparatus of the two-phase SRM includes a plurality of independent diodes separated from a switch device, a manufacturing cost increases and a large manufacturing space is required.
[Patent Document]    Korean Patent Laid-Open Publication No. 2010-0115209